The number 81804
81804 is a composite number with 24 divisors. Its prime factorisation is × 3 × 17 × 401. Divisors (24): 1, 2, 3, 4, 6, 12, 17, 34, 51, 68, 102, 204, 401, 802, 1203, 1604 … 81804.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
81804 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
81804 is composite. Its prime factorisation is
- 3
The divisors add up to 202608; without 81804 itself that is 120804, so 81804 is abundant (120804 is more than 81804). Euler's totient φ(81804) = 25600 numbers up to 81804 share no factor with it.
- 4
The digits of 81804 add up to 21, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 63 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81804 = 2^{2} \times 3 \times 17 \times 401 \]81804 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 202608 |
| Euler totient φ(n) | 25600 |
| Square | 6691894416 |
| Cube | 547423730806464 |
| Square root | 286.013986 (= 2√20451) |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 63 |
| Scientific notation | 8.1804 × |
81804 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand eight hundred and four |
| Binary (base 2) | 10011111110001100 |
| Octal (base 8) | 237614 |
| Hexadecimal (base 16) | 13F8C |
| Base 3 | 11011012210 |
| As time | 81804 seconds = 22 h 43 min 24 s |
Is 81804 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (81804 ÷ 2 = 40902) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (81804 ÷ 3 = 27268) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (81804 ÷ 4 = 20451) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 4) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (81804 ÷ 6 = 13634) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 2) | A number is divisible by 7 if double the last digit and subtract it from the rest: the result is a multiple of 7. |
| 8 | No (remainder 4) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 3) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 4) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 8) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (81804 ÷ 12 = 6817) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 81804 a prime number?
No. 81804 = × 3 × 17 × 401, so it is divisible by 2.
What are the factors of 81804?
1, 2, 3, 4, 6, 12, 17, 34, 51, 68, 102, 204, 401, 802, 1203, 1604, 2406, 4812, 6817, 13634, 20451, 27268, 40902, 81804.
What is 81804 in binary?
10011111110001100 (hexadecimal 13F8C, octal 237614).
What is the square root of 81804?
About 286.0140, exactly 2√20451.
Is 81804 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 81804?
It is a composite number with 24 divisors.